In the model itself

That puts the information into the model object directly and its config. And then access is available directly from the object or indirectly from its config method. E.g., within subs/methods of your model class you can see–

You can also add methods to your model so that getting the data is less susceptible to typos; e.g., $self->{arg}->[1]. The following will give you a read only (ro) args method to an array reference of strings and not just an {args} hash reference.